6-Month Evaluation of the Zero Ischemia Coronary Anastomotic Connector in an Off-Pump Porcine Bypass Model
David Stecher, Gerard Pasterkamp, Lex A. van Herwerden, Marc P. Buijsrogge.
University Medical Center Utrecht, Utrecht, Netherlands.
OBJECTIVE: To facilitate minimal access CABG, a simplified alternative for hand-sutured anastomosis has to be developed. This study evaluated the zero ischemia ELANA (Excimer Laser Assisted Non-occlusive Anastomosis) coronary connector at 6 months in the porcine OPCAB model (equivalent to a 2-year healing response in human coronary arteries), with regard to anastomotic healing, remodeling and hemodynamic function. Initial mid-term results (5 weeks, n=12) in the same model showed that the coronary connector is easy-to-use, feasible and safe, and all anastomoses were fully patent with streamlining neointimal coverage along the circumference of the anastomosis.
METHODS: In 2 animals, LITA-to-LAD and in 1 animal, LITA-to-LAD and RITA-to-RCA bypasses were evaluated intraoperatively and at 6 months (n=4; coronary inner diameter [ID] 2.5 mm). The anastomoses (n=4) were examined by angiography, fractional flow reserve (FFR), coronary flow reserve (CFR), flow measurement, scanning electron microscopy (SEM; n=1), histology (n=2), optical coherence tomography (OCT; n=1) and intravascular ultrasound (IVUS; n=1).
RESULTS: All anastomoses (n=4) were fully patent (FitzGibbon grade A) at follow-up with a FFR of 0.88 ± 0.03 and a CFR of 4.3 ± 0.7 (coronary ID 2.5 mm preoperative, 4 mm at 6 months). Intraoperative mean peak hyperemic flow response after 30-second graft occlusion was 4.3 ± 1.3. SEM demonstrated complete endothelial coverage of the anastomotic surface and histology showed minimal intimal hyperplasia at 6 months (see figure; C=connector; IH=intimal hyperplasia). At follow-up, IVUS and OCT confirmed histologic findings, and OCT measurements demonstrated limited neointima formation with a 0.06 mm intimal coverage of the intraluminal part of the connector.
CONCLUSIONS: The zero ischemia coronary connector showed an excellent healing response on the long-term in the porcine OPCAB model, and hence has potential for minimally invasive CABG. Despite the relatively undersized anastomosis at 6 months due to the growth of the porcine coronaries over 6 months, excellent anastomotic healing and remodeling were demonstrated. Safety and quality of the anastomoses on small caliber coronaries still has to be assessed.
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